DDJ SB3 controller works, but no sound

I bought a ddj-sb3 and have not been able to use it for weeks now since there is no sound coming out. I do not have an aux input on my speakers and have been trying to plug the master (red and white) cords that plug into the back of the mixer, into every possible aux output on my computer but nothing works. I downloaded the latest driver, I reinstalled serato dj pro multiple times. I even built a completely new PC and still nothing works. Please help, I have been dying to use my board and still cannot.